Journal of Civil Engineering Research 2016, 6(1): 1-6 DOI: 10.5923/j.jce.20160601.01 Assessment of Concrete Produced with Foundry Waste as Partial Replacement for River Sand T. C. Nwofor 1,* , C. Ukpaka 2 1 Department of civil Engineering, University of Port Harcourt, Port Harcourt, Nigeria 2 Jospaka Ventures Nigeria Limited, Port Harcourt, Nigeria Abstract The assessment in this research is targeted at determining the percentage of foundry waste suitable to be used as a partial replacement for fine sand aggregate. Experimental result reveals that 15% of foundry sand is appropriate as partial replacement of fine sand aggregate for preparation of grade 20 concrete by application of compressive strength equation as targeted strength of concrete were established at 28 days. The mathematical tools known as least square model was also applied to simulate the best equation of the curve for the purpose of prediction of compressive strength for the design of WFS concrete. The equation of best fit is given as Ϭ = 13.77wfs + 13.65 for 7 days and 28 days and Ϭ = 1.303wfs + 17.49 for 21 days. The developed equation illustrates the usefulness of least square model in monitoring the compressive strength of concrete upon the variation of percentage replacement with waste foundry sand. Keywords Concrete, Waste Foundry Sand, Fine Sand and Compressive Strength 1. Introduction The evaluation of engineering aggregate materials as good alternative replacement or partial replacement of aggregate in concrete production that will be affordable and durable is of global interest. Aggregates are the significant constituents in concrete. They give weight to the concrete and reduce shrinkage [1-3]. Assessment of foundry sand as a replacement for fine aggregate on fresh and hardened characteristics of concrete revealed that compressive strength of concrete decreases with increase in foundry sand [4-5]. Research conducted on fresh and hardened properties of grade 20 concrete, by substituting waste ferrous and non-ferrous foundry sand revealed that the compressive strength increased normally at 7days, however the strength gradually decrease as waste foundry sand content increased at 21 and 28 days, which is similar for other kind of replacements [6-14]. In terms of flexural strength, concrete strength increased with the increased in founding sand content at 28 days. This research is centered at investigating the foundry sand as an alternative for partial replacement of fine sand aggregate in the production of concrete, thereby making the waste founding sand in Nigeria a useful waste by applying the empirical formula for compressive strength for adequate mix design. * Corresponding author: temple.nwofor@uniport.edu.ng (T. C. Nwofor) Published online at http://journal.sapub.org/jce Copyright © 2016 Scientific & Academic Publishing. All Rights Reserved 2. Materials and Method 2.1. Cement R Dangote 3x Portland cement were used for batching and mixing of all specimens 2.2. Standard Grading Curve The grading patterns of aggregate can be shown on tables or charts. Expressing grading limits by means of charts gives a good pictorial view. The correlation of grading pattern of a number of samples can be made at one glance. This is the reason, often grading of aggregates is shown by means of grading curves. Practical knowledge has revealed that in practice it is difficult to get the aggregate to conform to any one particular standard curve exactly where concrete of high strength and good durability is required, time aggregate zones may be used, but the concrete mix should be properly designed. If the fine aggregate grading becomes progressively finer, that is from aggregate to coarse aggregate should be progressively reduced. The most suitable fine to coarse rating of aggregate to be applied for any particular mix will depend on the grading particle shape and surface texture of both fine and coarse aggregates. 2.3. Water The quantity and quality of water used during the batching of the concrete is of good one and based on water / cement adopted as water is a significant ingredient of concrete as it actively participates in the chemical reaction with cement.